Method of and machine for sealing mounts into bulbs



M. WILDEBOER 1,723 METHOD OF AND MACHINE FOR SEALING MOUNTS INTO BULBS Filed 001;. 27, 1927 n 5 e Mum/rm m ft m A F m m w u w M 6 w 2 577H .7 f\\ a J, v m

Patented Aug. 6, 1929.

omen STATES 1,723,107 OFFICE.

Maarnns wrtnnnonn, or EINDHOVEN, NETHERLANDS, nssrsnon 'ro enunaar. ELEG- rnro COMPANY, A conrona'rron or new roan.

METHOD OF AND MACHINE FOE SEALING MOUNTS INTO BULBS.

Application filed October 27,1927, Serial No. 229,183, and in the Netherlands November 10, 1926.

This invention refers to a method of and machine for sealing amount into a bulb during the manufacture of electric incandescent lamps or similar devices. Usually the sealing-in is done by placing the bulb and the mount in proper relative position and then either rotating the bulb in the sealing-1nflame to heat it, or holding the bulb stationary and moving the sealing-in burners around it during the heating. Both methods are based on the principle that it is necessary to move the flame relative to the bulb in order to obtain as uniform heating of the glass as possible. I he method of the present invention departs entirely from this prior practice, and in accordance with this invention the seal1ngin is done by means of flames which encircle the bulb and are stationary with respect to 26 the glass of the bulb. During thesealing-in an eilort is usually made to taper that part of the bulb neck between the bulb and the flame of the mount.- By the usual sealing-in methods the tapering of the bulb neck may be done by moving the flame up and down in a direction parallel to the longitudinal axis of the bulb. However, if the flame remains, stationary, it is necessary'to try to produce the same effect by giving the flame a definite shape and a definite direction. I 0

According to the invention the flame is given the shape of the surface of a frustum of a cone and is directed at an acute angle to the surface of the glass. The desired conical part may then be obtained by means of this shape and direction of the flame, as the glass possesses, in general, the tendency when fused to deform in such a way as to take up a position beyond range of the flame. If both the bulb and the flame are stationary the possibility arises that cutting oil the superfluous part of the bulb will not be as easy as where the prior sealing-in-methods are used. According to the invention, horizontal flames have been provided for this purpose, which are located in the plane of that part of the bulb which is sealed to the mount and which are directed toward the bulb. Thus, that 7 portion of the neck of the bulb, which ex- 0 tends beyond the seal, is cut oil quickly and certainly with the assurance that no superfluous glass will remain attached to the rim of the flange of the mount.

In accordance with the invention the machine has been provided with a. stationary bulb support and a stationary sealing-in burner so constructed that it emits a flame shaped like the surface or" a'trustum of a cone which is coaxial with the axis of the bulb support. The design is perferably such that the'bulb support and the burner are constructed as a unit as this arrangement has the advantage of very simple construction and convenient supervision. I

The new method and the machine based upon 1t are of great value in constructing a comblned sealing in and exhausting machine. TlllS machine must be designed in such a way that the sealing-in and the exhaust of the lamp can take place in one and the same head for the bulb and the mount. This means that the mount support must be provided with a valve in the connection between the exhaust tube of the bulb and the pump. in case the V mount support rotates, a rotating high vacuum valve must be used but it, on the other hand, the mount support remains stationary then it is necessary to use rotating burners when following the old scaling in method. In both cases so many difliculties are encountered that only a few applications of them have been made in practice. However, if the sealing-in is done according to the method of the invention, both the mount support and the burner may be stationary, and consequently there are no difliculties encountered 1n uslng a valve, so that acombined sealingin and exhaust machine becomes practical.

According to the invention, the sealing-in and exhaust machine comprises an intermittently rotatable carrier to which non-rotatable supports for the bulb and the mount and also stationary burners are fastened, while valves are installed in the mount supports which can be connected to a vacuum pump I by means of a tube.

One form-of machine constructed in accordance with the invention is shown on the attached drawing, in which-- Fig. 1 is a view, part1 in cross section of a head comprising a bu b support also constructed to act as a burner, and a mount support in which there is a valve for the vacuum connection; Figures 2, 3 and 4 are diagrammatic views of the various sta es of the sealing-in process to which the bul is subjected, and Figure 5-is a view, partly in cross section of a combined seal1ng-in and exhaust machine which will operate in accordance with the principle of the invention. no

The head shown in Figure 1 has a bulb a sealing-in burner comprising a chamber 11 with burner openings 12. By means of supply pipes the chamber 11 is fed from a mixmg chamber which supplies a mixture of gas and air or of gas and oxygen. Immediately below the sealing-in burner is a cut ofl burner 13 with burner openings 14 so placed that a horizontally directed cutting off flame will be emitted by them. In alignment with the bulb support is a mount support 15 with a bore 16 through which the exhaust tube 17 of the lamp can enter an exhaust head 18 mounted directly below the mount support and connected to a vacuum-line.

A cone shaped sealing-in flame 20 will be emitted by the sealing-in burner 11, as shown on the drawing. This sealing-in flame 20 strikes the surface of the glass bulb at an acute angle as indicated in Figures 1 and 2,

and since the glass rendered plastic by the heat ofthe flame will tend to take a position outside the range of the flame, the heated portion of the bulb will contract or taper, as indicated in Figure 3. As appears from this figure the contraction or tapering of the bulb Wlll be approximately the same as is obtained by the usual rotating method of sealing-in.

Owing to thisdeformation or tapering o the bulb as the glass is heated the neck of the bulb will touch the edge of the flange of the mount and the two will fuse to form the seal. In order to cut ofl properly the surplus portion 22 of the bulb neck which extends beyond the seal the horizontal flame of the cut ofl burner 13 is directed at the place of greatest contraction of the bulb neck, as shown in Fig une 4, so that the glass will melt ofl at that p ace.

One embodiment of the invention is shown in Figure 5 which illustrates a combined sealing-in and exhaust machine. The sealing-in heads, each comprising a bulb support 10 with a sealing-in burner 11 and a cutting off burner 13, mounted side by side and rigidly positioned with relation to the bulb su port, are fixed on a rotatable carrier or 'spidbr 25, in-

termittently rotated by gearing 25, and are" connected to the factory gas mains 29 through a gas supply pipe 26 mounted on and moving with the spider and connected to a valve 27, which rotates with the spider on a stationary valve seat 28 in order that the burners may be fed with gas during the rotation of the carrier 25 and can direct flames on the bulbs 30 in the bulb supports 10. The mounts 31 which are to be sealed into these bulbs are placed with their exhaust tubes in the mount supports 15 which constitute a part of the sealing in heads and which are in alignment with the axis of the bulb supports. The mounts on the mount supports are connected head 18 to an exhaust pipe 32 which, after the mounts have been sealed in and the lamps are ready for exhaustion, is automatically connected to a vacuum line 33 through ports in the rotating valve 27 and the stationary valve seat 28.

In the construction shown the sealing-in burners are annular members which also form the bulb supports 10 forthe bulbs 30. Each member has an annular opening for holding a bulb neck downward, and concentric with it is the annular chamber 11 in the inner wall of which are the openings 12 pointing inward and downward at an angle to the axis of the annular opening for holding the bulb, so that the gas issuing from these openings forms a flame having the shape of the surface of a frustum of a cone with its apex toward the cutting oif flame from the burner 13 and its base in the plane of the openings 12. The annular cuttin ofl' burner 13 is fixedsbeside the sealing-in urner to be coaxial with it and with the bulb holder 10,- and may, for example, be held in place by spacers 13 secured to the bulb support, so that the burners and the bulb support form a unitary structure.

It will be clear from the drawing that an extremely simple construction of the entire machine becomes possible owing to the new principle of sealing-in by which two of the most essential operations in the manufacture of incandescent lamps, viz the sealingin of the mount and the exhausting, can take place in a single machine, which can be attended to very easily, and which requires very little floor space in the factory.

What I claim as new and desire to secure by Letters Patent of the United States, is 2- I 1. The method of sealing the stem of a mount into the glass bulb of an incandescent lamp or similar article which consists in holding' the buIb and mount stationary in predetermined relation to each other, and heating a zone on said bulb adjacent the stem by an annulus of flame which is stationary with reference to said bulb and which encircles and is coaxial with the bulb and'is inclined to its longitudinal axis to heat the glass in said zone uniformly. i

2. The method of sealing the stem of a mount into the glass bulb of an incandescent lamp or similar article which consists in bolding the bulb and mount stationary in predetermined relation to each other, and heating a zone on said bulb adjacent the stem by flames side by side to form an annulus of flame which has the shape of the surface of a frustum of a cone coaxial with the longitudinal axis of the bulb and which encircles the bulb and is directed to engage the surface of the bulb at an acute angle adjacent the edge of the stem of the mount.

3. The method of sealing the stem of a v 6 through the mount supports and the exhaust mount into the glass bulb of an incandescent ing the bulb and mount stationaryin predetermined relation to each other, heating a zone on said bulb adjacent the stem by an annulus 'of flame stationary with reference to said bulb and encircling the bulb and directed to make an acute angle to it, and cutting off the surplus neck of the bulb by an annulus of flame which encircles thebulb neck and is per pendioular to it and is directed to engage said neck just below the stem.

4. In ,a device of the character described the combination of an annular bulb holder and a coaxial annular sealing in burner stationary with reference to said bulb holder and constructed to emit an annulus of flame having the shape of the surface of a frustum of a cone coaxial with the axis of said bulb support.

5. In a device of the character described the combination of an annular bulb holder and a coaxial annular sealing in burner rigidly secured to said bulb holder to form a unit therewith and constructed to emit an annulus of flame having the shape of the surface of a frustum of a cone coaxial with the axis of said bulb support.

6. In a device of the character described I the combination of a rotatable support and a plurality of sealing in heads on said suplport, each .head comprising a bulb support for olding a lamp bulb with its neck downward,

- an annular sealing in burner rigidly secured to said support to project toward the bulb an annulus of flame which encircles the bulb'neck i-bulbsupport, an annular cutting oil burner coaxial with said bulb support and rigidly secured thereto to project a flame towar and perpendicular to the axis of said bulb support, and a mount support for holding a mount in the axis of said bulbsupport with the edge of the stem adjacent the zone of contact of said flames with the neck of a bulb in said bulb support.

7 In a device of the character described a sealing-in head comprising an annular bulb support, an annular sealing-inburner, and an annular cutting ofi burner all rigidly mounted side by side to be coaxial, said cutting oil burner being constructed to emit an annulus of flame in a plane parallel to the plane of said bulb support, and said sealing-in burner being constructed to emit an annulus of flame having the shape of the surface of a frustum of a cone coaxial with said bulb support and with its apex toward the plane of said cutting oil burner.

8. In a device of the character described a unitary bulb support and sealing-in burner comprlsing a member having a tapered annular opening to receive a bulb and'a concentric annular chamber with a plurality of openings directed toward and at an angle to the axis of said member to supply gas for maintaining an annulus of flame shaped like the surface of a frustum of a cone coaxial with said annular opening and having its base in the plane of said openings.

' In witness whereof I have hereunto set my hand this first day of October, 1927.

MARINUS WiLnEBoER. 

